The present invention relates to a collapsible walker for elderly and disabled individuals and, more particularly, relates to a locking device in the form of an integral locking mechanism and release button for locking the side frames of the walker in an open position.
Walkers are a necessity to many elderly and disabled individuals and must accompany them wherever they go. Therefore, walkers must be capable of being folded to a flat position to facilitate their shipment or storage. Since folding or unfolding of a walker will likely have to be accomplished by the disabled person, without outside assistance, the folding mechanism should be easily operable even by the elderly or disabled whose muscular coordination might be impaired. For example, walkers should be constructed to enable the elderly and disabled to maneuver themselves and their walkers into and out of automobiles. A cumbersome mechanism for folding and unfolding a walker might limit its range of usefulness.
An essential requirement for a walker is that it provide firm support for the user. An elderly or disabled person using the walker may have a poor sense of equilibrium and a genuine fear of falling. Given these circumstances, nothing can be more unnerving than a walker which feels unstable. Collapsible walkers frequently develop a certain feeling of looseness at joints or pivot points resulting from the constant folding and unfolding of the walker. Therefore, it is desirable to provide collapsible walkers which do not develop looseness through continued usage.
The foregoing objectives have been tackled by the prior art as exemplified by several U.S. Pat. Nos. Thus, U.S. Pat. No. 4,180,086 describes a walker 10 that can be locked in a normal open position by a tubular telescoping locking means 32. The locking means consists of a first tube 54 which telescopes and is received by a second outer tube 52, with one of the tubes being connected to the front cross-rib 14 and the other to the rear leg of the side frame of the walker.
One of the tubes includes an aperture which guides and contains the head of a pushbutton. The second tube includes apertures 55 and 56 which are adapted to receive and lock a pushbutton 58. A palm pusher 44 operates, in the manner described in U.S. Pat. No. 4,056,115, to displace the locking pushbutton from the aperture to permit the two tubes to slide relative to one another to position the walker.
In U.S. Pat. No. 3,945,389, the locking means are comprised of corner ribs, each of which includes a plate member 46 and which, as shown in FIGS. 5-7, is pivotally supported with respect to one of the upper ribs by a pivot pin 48. A guide pin 50 engages a guide slot in the plate member 46. A plastic washer 60 pressed against the plate member provides frictional resistance to sliding. To lock the walker in its closed or open position, the corner ribs are interlocked with the cross-rib 4 by means of a detent 62 that has a head 63 that extends through an aperture 68 in the upper surface of a transverse member 12. The detent 62 is biased to an upward position by a spring 66.
Additional collapsible walker embodiments are described in U.S. Pat. Nos. 3,442,276; 3,658,079; 3,783,886; and 3,688,789.
In the case of the aforementioned No. 4,180,086 patent, the comparatively long telescoping tubes are more susceptible to develop a resistance to sliding and more prone to jamming The general construction thereof is mere complex and less sturdy. In the locking arrangement of United States Patent 3,945,389, the construction of the locking mechanism is similarly more prone to jamming and is constructed of numerous parts, adversely affecting long term reliability and operability. Moreover, the guide slot in the plate member is susceptible of catching clothing, such as the sleeve, of the user, or even a finger, and is thus liable to cause injury.
The general trend in the medical field is on reducing cost and increasing reliability of medically related equipment in order to contain the upwardly spiraling costs of medicine in the U.S.